information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

A red seaweed (Heterosiphonia plumosa)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.



Heterosiphonia plumosa is a red to deep crimson seaweed which appears black when dried. This species has a flattened, fern-like appearance with a hairy thallus growing from a discoid holdfast. The fronds are flat or slightly cylindrical up to 20 cm in length and 0.5 cm in diameter at the base, tapering towards the apex. The primary branching from the main frond occurs in a single plane, and is alternately, yet irregularly spaced with up to 1 cm between each branch. Each branch is bare at the base, with the rest bearing an irregular and alternately arranged series of smaller secondary branches. The secondary branches are progressively shorter towards the apex, and each branch bears numerous pointed branchlets giving an overall tufted and feather-like appearance.

Recorded distribution in Britain and Ireland

Widely recorded throughout the coasts of Britain and Ireland, especially the south west but is rarely recorded on the north east Scottish coasts.

Global distribution



This species grows on rocks and as an epiphyte on seaweeds such as Laminaria in the lower littoral and sublittoral.

Depth range


Identifying features

  • Red to deep crimson in colour.
  • Hairy thallus up to 20 cm in length and 0.5 cm in diameter at the base.
  • The holdfast is discoid.
  • Alternate and irregular primary and secondary branching.
  • Additional branchlets give a feather-like appearance.

Additional information

Heterosiphonia plumosa is a perennial (life cycle >2 years) species, reproducing mainly during the summer and autumn. The cystocarps of Heterosiphonia plumosa are ovate and borne near the base of the branchlets, as are the tetrasporangia in asexual individuals, which are lanceolate and stalked (Dickinson, 1963). Both can be easily distinguished under a hand lens.

Heterosiphonia plumosa has several recorded variations, most notably Heterosiphonia plumosa f. palens which is typically slender and up to 7.5 cm in length. The fronds are smooth with evenly spaced branches and commonly occurs in deeper coastal waters (Dickinson, 1963).

Listed by

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Further information sources

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  1. Dickinson, C.I., 1963. British seaweeds. London & Frome: Butler & Tanner Ltd.

  2. Foster-Smith, J. (ed.), 2000. The marine fauna and flora of the Cullercoats District. Marine species records for the North East Coast of England. Sunderland: Penshaw Press, for the Dove Marine Laboratory, University of Newcastle upon Tyne.

  3. Gibson, R., Hextall, B. & Rogers, A., 2001. Photographic guide to the sea and seashore life of Britain and north-west Europe. Oxford: Oxford University Press.

  4. Hiscock, S., 1986b. A field key to the British Red Seaweeds. Taunton: Field Studies Council. [Occasional Publication No.13]

  5. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  6. Laverack, M.S. & Blackler, D.M., 1974. Fauna & Flora of St. Andrews Bay. Scottish Academic Press (Edinburgh & London).

  7. Maggs, C.A. & Hommersand, M.H., 1993. Seaweeds of the British Isles: Volume 1 Rhodophycota Part 3A Ceramiales. London: Natural History Museum, Her Majesty's Stationary Office.

  8. MarLIN (Marine Life Information Network), 2005. SEArchable BEnthic Data (SEABED) Map [on-line]. Data Access Sub-programme, Marine Life Information Network for Britian and Ireland,

  9. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset accessed via on 2018-09-25.

  2. Fenwick, 2018. Aphotomarine. Occurrence dataset Accessed via on 2018-10-01

  3. Kent Wildlife Trust, 2018. Biological survey of the intertidal chalk reefs between Folkestone Warren and Kingsdown, Kent 2009-2011. Occurrence dataset: accessed via on 2018-10-01.

  4. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: accessed via on 2018-10-01.

  5. Manx Biological Recording Partnership, 2017. Isle of Man wildlife records from 01/01/2000 to 13/02/2017. Occurrence dataset: accessed via on 2018-10-01.

  6. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset: accessed via on 2018-10-01.

  7. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset: accessed via on 2018-10-01.

  8. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1995 to 1999. Occurrence dataset: accessed via on 2018-10-01.

  9. National Trust, 2017. National Trust Species Records. Occurrence dataset: accessed via on 2018-10-01.

  10. NBN (National Biodiversity Network) Atlas. Available from:

  11. OBIS (Ocean Biogeographic Information System),  2019. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2019-04-24

  12. Outer Hebrides Biological Recording, 2018. Non-vascular Plants, Outer Hebrides. Occurrence dataset: accessed via on 2018-10-01.

  13. Royal Botanic Garden Edinburgh, 2018. Royal Botanic Garden Edinburgh Herbarium (E). Occurrence dataset: accessed via on 2018-10-02.

  14. South East Wales Biodiversity Records Centre, 2018. SEWBReC Algae and allied species (South East Wales). Occurrence dataset: accessed via on 2018-10-02.


This review can be cited as:

Rowley, S.J. 2008. Heterosiphonia plumosa A red seaweed. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 24-04-2019]. Available from:

Last Updated: 03/07/2008